merlin_typer: clear Cmt_format between type steps
merlin_typer: clear Cmt_format between type steps

fxfactorial/merlin,rgrinberg/merlin,dra27/merlin,the-lambda-church/merlin,dra27/merlin,dra27/merlin,rgrinberg/merlin,dra27/merlin,rgrinberg/merlin,rgrinberg/merlin,the-lambda-church/merlin,fxfactorial/merlin,ocaml/merlin,ocaml/merlin,the-lambda-church/merlin,fxfactorial/merlin,ocaml/merlin,ocaml/merlin,fxfactorial/merlin